How do I make the ends of a pole less square?
To make subdivided edges look as expected make the corner loops follow the curvature of the desired shape (i.e. circle).

In this case, dissolve quad face in the middle (select edges, press X > Dissolve Edges), inset resulting Ngon twice (press I with face selected), select inner edge loop and merge it at center (Alt+M > At Center).



Note that you might want to dissolve also 4 edges in the resulting cap to get rid of tris.